The weakness of the Labour leadership, with its associated faction-fight, turns out to be quite useful:

Doubts about the political viability of Lord Mandelson’s plans to part-privatise Royal Mail are spreading through government, as the recent bout of Labour indiscipline underlines the political risks of confronting backbenchers.

The business secretary’s team are “proceeding as planned” with the core proposal to sell a 30 per cent stake in the state-owned postal operator to a foreign rival, which MPs are due to vote on before the summer.

But Gordon Brown’s recent Commons defeat over Gurkhas and the part-climbdown over MPs’ expenses has intensified concerns about the Royal Mail stand-off, convincing some senior ministers the government must give way.

Lord Mandelson believes the reforms are essential. He wants the chance to press his case to Labour backbenchers in the Commons, after seeing the positive effect that a “convincing argument” has recently made in the Lords. He still has the backing of Mr Brown, who remains convinced the reforms are urgently required.

But Lord Mandelson is not expected to take it to the wire if opponents were to win their case to delay or to redraw the plan because of the inability or unwillingness of whips to bring round rebels.

The call for a rethink by figures closely involved in pushing the Royal Mail bill reflects fears it will be impossible to pass the proposals without the support of scores of Tory MPs, which will be a heavy blow to Mr Brown’s authority.